Prepreg resin composition, prepreg and molded article

ABSTRACT

Provided is a prepreg resin composition, containing: a urethane (meth)acrylate (A) that is a reaction product of polyisocyanate (a1), polyol (a2), and hydroxy alkyl (meth)acrylate (a3); a polymerization initiator (B); and a thermoplastic resin (C), as an essential component, in which the polyisocyanate (a1) is at least one polyisocyanate selected from 2,4′-diphenyl methane diisocyanate, 4,4′-diphenyl methane diisocyanate, a carbodiimide modified product of 4,4′-diphenyl methane diisocyanate, and polymethylene polyphenyl polyisocyanate. The prepreg resin composition of the invention is excellent in molding properties, and is capable of forming a molded article excellent in various physical properties such as flexibility, impact resistance, and heat resistance, and thus, can be preferably used in a prepreg and a molded article thereof.

TECHNICAL FIELD

The present invention relates to a prepreg that is excellent inworkability and molding properties and is capable of forming a moldedarticle excellent in various physical properties such as heatresistance, and to a molded article thereof.

BACKGROUND ART

Fiber-reinforced resin composite materials which are reinforced withreinforcing fibers such as carbon fibers or glass fibers have drawnattention in terms of their light-weight and characteristics such asexcellent heat resistance or mechanical strength, and the use of thefiber-reinforced resin composite materials is expanding in variousstructural applications such as casing bodies or various members forautomobiles and airplanes. Such fiber-reinforced resin compositematerials are formed using, for example, a method in which anintermediate material called a prepreg, which is obtained byimpregnating reinforcing fibers with a thermosetting resin, is used andsubjected to curing and molding by autoclave molding or press molding,as a molding method.

In general, resins for prepregs are required to have both stability at aroom temperature and the ability to be cured by heating or the like, andthus, in general, thermosetting resins such as epoxy resin compositionsare frequently used for prepregs. However, the prepregs using the epoxyresins have a problem in that the prepregs are cured at a roomtemperature, and thus, need to be stored under refrigerated conditions.

In order to solve such a problem, a molding material that is capable ofachieving high productivity and stability at a room temperature has beendeveloped (for example, refer to PTL 1). The molding material contains aurethane (meth)acrylate compound having a specific structure, and areinforcing fiber, but is insufficient for molding properties that arerequired for the prepregs.

Therefore, there has been a need for a material that has excellentworkability and molding properties and is capable of forming a moldedarticle excellent in various physical properties such as flexibility,impact resistance, and heat resistance.

CITATION LIST Patent Literature

PTL 1: JP-A-2016-29133

SUMMARY OF INVENTION Technical Problem

An object to be achieved by the invention is to provide a prepreg resincomposition that is excellent in molding properties and is capable offorming a molded article excellent in various physical properties suchas flexibility, impact resistance, and heat resistance, and a prepregand a molded article thereof.

Solution to Problem

The present inventors have found that a prepreg resin compositioncontaining specific urethane (meth)acrylate, a polymerization initiator,and a thermoplastic resin, as an essential raw material, and a prepregare excellent in molding properties, and are capable of forming a moldedarticle excellent in various physical properties such as flexibility,impact resistance, and heat resistance, and thus, have completed theinvention.

That is, the invention relates to a prepreg resin composition,containing: a urethane (meth)acrylate (A) that is a reaction product ofpolyisocyanate (a1), polyol (a2), and hydroxy alkyl (meth)acrylate (a3);a polymerization initiator (B); and a thermoplastic resin (C), as anessential component, in which the polyisocyanate (a1) is at least onepolyisocyanate selected from 2,4′-diphenyl methane diisocyanate,4,4′-diphenyl methane diisocyanate, a carbodiimide modified product of4,4′-diphenyl methane diisocyanate, and polymethylene polyphenylpolyisocyanate, and a prepreg and a molded article thereof.

Advantageous Effects of Invention

A molded article obtained from the prepreg resin composition and theprepreg of the invention is excellent in flexibility, impact resistance,heat resistance, and the like, and thus, can be preferably used inautomotive members, railroad car members, airspace craft members, shipmembers, house facility members, sports members, light-weight vehiclemembers, construction and civil engineering members, case bodies for OAinstrument, and the like.

DESCRIPTION OF EMBODIMENTS

A prepreg resin composition of the invention is a prepreg resincomposition, containing: a urethane (meth)acrylate (A) that is areaction product of polyisocyanate (a1), polyol (a2), and hydroxy alkyl(meth)acrylate (a3); a polymerization initiator (B); and a thermoplasticresin (C), as an essential component, in which the polyisocyanate (a1)is at least one polyisocyanate selected from 2,4′-diphenyl methanediisocyanate, 4,4′-diphenyl methane diisocyanate, a carbodiimidemodified product of 4,4′-diphenyl methane diisocyanate, andpolymethylene polyphenyl polyisocyanate.

The urethane (meth)acrylate (A) is the reaction product of thepolyisocyanate (a1), the polyol (a2), and the hydroxy alkyl(meth)acrylate (a3).

The polyisocyanate (a1) is one or more kinds of polyisocyanates selectedfrom the 2,4′-diphenyl methane diisocyanate, the 4,4′-diphenyl methanediisocyanate, the carbodiimide modified product of the 4,4′-diphenylmethane diisocyanate, and the polymethylene polyphenyl polyisocyanate,and it is preferable that the polyisocyanate (a1) contains thepolymethylene polyphenyl polyisocyanate from the viewpoint of furtherimproving heat resistance of a molded article.

Other polyisocyanates in addition to the polyisocyanate (a1) can be usedtogether as an isocyanate raw material of the urethane (meth)acrylate(A). For example, a nurate modified product of diphenyl methanediisocyanate, a biurette modified product, a urethane imine modifiedproduct, polyol modified product that is modified with polyol having anumber average molecular weight of 1,000 or less, such as diethyleneglycol or dipropylene glycol, aromatic polyisocyanate such as tolylenediisocyanate (TDI), tolidine diisocyanate, xylene diisocyanate,1,5-naphthalene diisocyanate, and tetramethyl xylene diisocyanate;alicyclic polyisocyanate such as isophorone diisocyanate (IPDI),hydrogenerated diphenyl methane diisocyanate, hydrogenerated xylenediisocyanate, and norbornene diisocyanate; hexamethylene diisocyanate, anurate modified product of hexamethylene diisocyanate, a biurettemodified product, an adduct, aliphatic polyisocyanate such as dimericacid diisocyanate, and the like can be used as the other polyisocyanate.

The polyisocyanate (a1) is preferably 20% by mass or more, and is morepreferably 50% by mass or more, in the isocyanate raw material of theurethane (meth)acrylate (A).

The polyol (a2) is not particularly limited, for example, an alkyleneoxide adduct of bisphenol A, an alkylene oxide adduct of aromatic diol,polyester polyol, acryl polyol, polyether polyol, polycarbonate polyol,polyalkylene polyol, and the like can be used. Such polyols (a2) can beindependently used, or two or more kinds thereof can also be usedtogether.

Examples of the hydroxy alkyl (meth)acrylate (a3) include 2-hydroxyethyl (meth)acrylate, 3-hydroxy propyl (meth)acrylate, 4-hydroxy-n-butyl(meth)acrylate, 2-hydroxy propyl (meth)acrylate, 2-hydroxy-n-butyl(meth)acrylate, and 3-hydroxy-n-butyl (meth)acrylate, and the 2-hydroxyethyl (meth)acrylate is preferable. Note that, such hydroxy alkyl(meth)acrylates (a3) can be independently used, or two or more kindsthereof can also be used together.

It is preferable that the hydroxy alkyl (meth)acrylate (a3) is a rangeof 5% by mass to 50% by mass, in the prepreg resin composition.

A molar ratio (NCO/OH) of an isocyanate group (NCO) of an isocyanatecompound, containing the raw material of the urethane (meth)acrylate(A), to a hydroxyl group (OH) of a compound having a hydroxyl group ispreferably 0.7 to 1.5, is more preferably 0.8 to 1.3, and is even morepreferably 0.8 to 1.0.

The polymerization initiator (B) is not particularly limited, but anorganic peroxide is preferable, and a diacylperoxide compound, aperoxyester compound, a hydroperoxide compound, a ketone peroxidecompound, an alkyl perester compound, a percarbonate compound,peroxyketal, and the like are exemplified and can be suitably selectedin accordance with a molding condition. Note that, such polymerizationinitiators (B) can be independently used, or two or more kinds thereofcan also be used together.

In addition, among them, in order to shorten a molding time, it ispreferable to use a polymerization initiator in which a temperature forobtaining 10-hour half life is 70° C. or higher and 100° C. or lower. Itis preferable that the temperature is 70° C. or higher and 100° C. orlower, since the life of the prepreg at a room temperature increases,and curing can be performed for a short period of time (within 5minutes) by heating, and the polymerization initiator is combined withthe prepreg of the invention, and thus, more excellent ability to becured and molding properties are obtained. Examples of thepolymerization initiator include1,6-bis(t-butylperoxycarbonyloxy)hexane,1,1-bis(t-butylperoxy)cyclohexane, 1,1-bis(t-amylperoxy)cyclohexane,1,1-bis(t-hexylperoxy)cyclohexane, t-butylperoxy diethyl acetate,t-butylperoxyisopropyl carbonate, t-amylperoxyisopropyl carbonate,t-hexylperoxyisopropyl carbonate,di-tert-butylperoxyhexahydroterephthalate,t-amylperoxytrimethylhexanoate, and t-hexylperoxy-2-ethylhexanoate.

It is preferable that the content of the polymerization initiator (B) isin a range of 0.3% by mass to 3% by mass, in the prepreg resincomposition, from the viewpoint of excellent curing properties andstorage stability.

Examples of the thermoplastic resin (C) include a polyurethane resin, apolyamide resin, a polyethylene terephthalate resin, a polybutyleneterephthalate resin, a polycarbonate resin, a polypropylene resin, apolyethylene resin, a polystyrene resin, an acryl resin, a polybutadieneresin, a polyisoprene resin, and products thereof modified bycopolymerization, and among them, a thermoplastic polyurethane resin ispreferable, and a thermoplastic polyurethane containing polyalkyleneether polyol as an essential raw material is more preferable, from theviewpoint of further improving flexibility, impact resistance, and heatresistance of a molded article to be obtained. Such thermoplastic resinscan be independently used, or two or more kinds thereof can also be usedtogether.

In addition, the thermoplastic resin (C) can also be used by being addedin a particulate state, or can also be used by being melted and mixed.In the case of using the thermoplastic resin in a particulate state, thediameter of the particles is preferably 30 μm or less, and is morepreferably 20 μm or less, from the viewpoint of dispersibility withrespect to a fiber.

It is preferable that the content of the thermoplastic resin (C) is in arange of 1% by mass to 25% by mass, in the prepreg resin composition,from the viewpoint of further improving of the flexibility, the impactresistance, and the heat resistance of the molded article to beobtained.

In addition, as necessary, an ethylenically unsaturated monomer may beused as the raw material of the prepreg resin composition of theinvention. Examples of the ethylenically unsaturated monomer include astyrene compound such as styrene, methylstyrene, halogenated styrene,and divinylbenzene; a monofunctional (meth)acrylate compound such asmethyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate,butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl(meth)acrylate, isobornyl (meth)acrylate, benzyl (meth)acrylate,methylbenzyl (meth)acrylate, phenoxyethyl (meth)acrylate,methylphenoxyethyl (meth)acrylate, morpholine (meth)acrylate,phenylphenoxyethyl acrylate, phenylbenzyl (meth)acrylate, phenylmethacrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl(meth)acrylate, and dicyclopentanyl methacrylate; a hydroxylgroup-containing (meth)acrylate compound such as hydroxyethyl(meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxybutyl(meth)acrylate; a di(meth)acrylate compound such as ethylene glycoldi(meth)acrylate, propylene glycol di(meth)acrylate, 1,4-butane dioldi(meth)acrylate, 1,6-hexane diol di(meth)acrylate, bisphenoldi(meth)acrylate, and 1,4-cyclohexanedimethanol di(meth)acrylate. Suchethylenically unsaturated monomers can be independently used, or two ormore kinds thereof can also be used together.

Among them, monofunctional (meth)acrylate having a molecular weight of150 to 250 is preferable, the phenoxyethyl (meth)acrylate, themethylphenoxyethyl (meth)acrylate, the benzyl (meth)acrylate, and themethylbenzyl (meth)acrylate are more preferable, and the phenoxyethyl(meth)acrylate and the benzyl (meth)acrylate are even more preferable,from the viewpoint of mechanical strength and heat resistance of amolded article for handling malodor and a hazardous product in a workenvironment.

The ethylenically unsaturated monomer in the prepreg resin compositionof the invention is preferably 50% by mass or less, and is morepreferably 30% by mass or less, from the viewpoint of a balance inworkability (tack properties), the heat resistance, and the ability tobe cured.

Components other than those described above may be used as the componentof the prepreg resin composition of the invention, and for example, athermosetting resin, a polymerization inhibitor, a curing promoter, afiller, a low shrinkage agent, a releasing agent, a thickening agent, aviscosity-reducing agent, a pigment, an anti-oxidant, a plasticizer, aflame retardant, an anti-micorbial agent, a UV stabilizer, a reinforcingagent, a photocuring agent, and the like can be contained.

Examples of the thermosetting resin include a vinyl ester resin, anunsaturated polyester resin, a phenol resin, a melamine resin, and afuran resin. In addition, such thermosetting resins can be independentlyused, or two or more kinds thereof can also be used together.

Examples of the polymerization inhibitor include hydroquinone,trimethylhydroquinone, p-t-butylcatechol, t-butylhydroquinone,toluhydroquinone, p-benzoquinone, naphthoquinone, hydroquinonemonomethyl ether, phenothiazine, copper naphthenate, and copperchloride. Such polymerization inhibitors can be independently used, ortwo or more kinds thereof can also be used together.

Examples of the curing promoter include metal soaps such as cobaltnaphthenate, cobalt octenate, vanadyl octenate, copper naphthenate, andbarium naphthenate, and a metal chelate compound such as vanadylacetylacetate, cobalt acetyl acetate, and iron acetylacetonate. Inaddition, examples of amines include N,N-dimethylamino-p-benzaldehyde,N,N-dimethylaniline, N,N-diethylaniline, N,N-dimethyl-p-toluidine,N-ethyl-m-toluidine, triethanolamine, m-toluidine, diethylenetriamine,pyridine, phenylmorpholine, piperidine, and diethanolaniline. Suchcuring promoters can be independently used, or two or more kinds thereofcan also be used together.

Examples of the filler include an inorganic compound and an organiccompound, and the filler can be used for adjusting the physicalproperties of the molded article such as strength, elasticity, impactstrength, and fatigue durability.

Examples of the inorganic compound include calcium carbonate, magnesiumcarbonate, barium sulfate, mica, talc, kaolin, clay, celite, asbestos,barite, barita, silica, siliceous sand, dolomite limestone, gypsum, analuminum finer powder, a hollow balloon, alumina, a glass powder,aluminum hydroxide, galuberite, zirconium oxide, antimony trioxide,titanium oxide, molybdenum dioxide, and an iron powder.

Examples of the organic compound include a natural polysaccharide powdersuch as cellulose or chitin, and a synthetic resin powder, and a powderof organic materials configured of a hard resin, soft rubber, and anelastomer or a polymer (a copolymer) or particles having a multilayerstructure such as a core-shell structure can be used as the syntheticresin powder. Specifically, acryl particles, polyamide particles,particles formed of butadiene rubber and/or acryl rubber, urethanerubber, silicon rubber, and the like, a polyimide resin powder, afluororesin powder, a phenol resin powder, and the like are exemplified.Such fillers can be independently used, or two or more kinds thereof canalso be used together.

Examples of the releasing agent include zinc stearate, calcium stearate,paraffin wax, polyethylene wax, and carnauba wax. The paraffin wax, thepolyethylene wax, the carnaubawax, and the like are preferable. Suchreleasing agents can be independently used, or two or more kinds thereofcan also be used together.

For example, a metal oxide or a metal hydroxide such as magnesium oxide,magnesium hydroxide, calcium oxide, and calcium hydroxide,microparticles of acrylic resin, and the like are exemplified as thethickening agent, and can be suitably selected in accordance withhandling properties of the prepreg of the invention. Such thickeningagents can be independently used, or two or more kinds thereof can alsobe used together.

The prepreg of the invention contains the prepreg resin composition andthe reinforcing fiber (D), and examples of the reinforcing fiber (D)include an organic fiber such as a carbon fiber, a glass fiber, asilicon carbide fiber, an alumina fiber, a boron fiber, a metal fiber,an aramid fiber, a vinylon fiber, and a tetoron fiber, and among them,the carbon fiber or the glass fiber is preferable, and the carbon fiberis more preferable, from the viewpoint of obtaining a molded articlehaving higher strength and higher elasticity. Such reinforcing fibers(D) can be independently used, or two or more kinds thereof can also beused together.

Various carbon fibers such as a polyacrylonitrile-based carbon fiber, apitch-based carbon fiber, and a rayon-based carbon fiber can be used asthe carbon fiber, and among them, the polyacrylonitrile-based carbonfiber is preferable from the viewpoint of easily obtaining a carbonfiber having high strength.

The shape of the reinforcing fiber (D) is not particularly limited, areinforcing fiber tow in which reinforcing fiber filaments are tied up,a unidirectional material in which reinforcing fiber tows are aligned inone direction, a woven fabric or a reinforcing fiber cut short, or anon-woven fabric or paper formed of a reinforcing fiber cut short, andthe like are exemplified, and it is preferable that the unidirectionalmaterial is used as the reinforcing fiber, and is laminated and molded,since high mechanical and physical properties can be obtained.

In the case of using the reinforcing fiber cut short, it is preferableto use a carbon fiber cut to 2.5 mm to 50 mm, from the viewpoint offurther improving in-mold fluidity in molding and the externalappearance of the molded article.

In the case of the woven fabric, a sheet in which fiber bundles arealigned in one direction, represented by plain weave, twill weave,sateen weave, or a non-crimp fabric, a stitching sheet in which sheetslaminated by changing angles are stitched not to be loosened, and thelike are exemplified.

Weight per unit area of the reinforcing fiber (a weight per 1 m² of thefiber) is not particularly limited, but is preferably 10 g/m² to 650g/m². It is preferable that the weight per unit area is 10 g/m² or more,since unevenness in a fiber width is small, and mechanical physicalproperties are excellent. It is preferable that the weight per unit areais 650 g/m² or less, since the impregnation of the resin is excellent.The weight per unit area is even more preferably 50 g/m² to 500 g/m²,and is particularly preferably 50 g/m² to 300 g/m².

A content rate of the reinforcing fiber (D) in the prepreg of theinvention is preferably in a range of 20% by mass to 85% by mass, and ismore preferably in a range of 40% by mass to 80% by mass, from theviewpoint of further improving mechanical strength of a molded articleto be obtained.

The prepreg of the invention, for example, is obtained by Step 1 ofimpregnating the reinforcing fiber (D) with a resin solution in whichthe polyisocyanate (a1), the polyol (a2), the hydroxy alkyl(meth)acrylate (a3), the polymerization initiator (B), and thethermoplastic resin (C) are mixed, by using a known mixing machine suchas a planetary mixer and a kneader, of interposing the reinforcing fiberbetween PET release films from an upper surface, and of performingrolling with a rolling machine to obtain a sheet, and Step 2 of leavingthe sheet to stand at a room temperature to 50° C., and of reacting anisocyanate group of the polyisocyanate (a1) with a hydroxyl group of thepolyol (a2) and the hydroxy alkyl (meth)acrylate (a3). In addition, inStep 1, the polyisocyanate (a1), the polyol (a2), and the hydroxy alkyl(meth)acrylate (a3) can also be partially reacted in advance, for usewithin a range not impairing impregnating properties with respect to thefiber.

It is preferable that the thickness of the prepreg of the invention is0.02 mm to 1.0 mm. It is preferable that the thickness is 0.02 mm ormore, since handling for laminating is facilitated, and it is preferablethat the thickness is 1 mm or less, since the impregnation of the resinis excellent. It is more preferable that the thickness of the prepreg is0.05 mm to 0.5 mm.

As a method for obtaining a molded article from the prepreg obtained asdescribed above, for example, a method is used in which the prepreg ispeeled off from the PET release films, and 8 to 16 prepregs arelaminated, and then, are put into a mold heated in advance at 110° C. to160° C., and mold clamping is performed with a compression moldingmachine, the prepreg is shaped, and is cured by retaining a moldingpressure of 0.1 MPa to 10 MPa, and then, a molded article is taken out.In this case, a manufacturing method is preferable in which the thermalcompression molding is performed by retaining a mold temperature of 120°C. to 160° C. in a mold including a share edge structure, a prescribedtime for 1 minute to 2 minutes per a thickness of 1 mm of a moldedarticle, and a molding pressure of 1 MPa to 8 MPa.

The molded article obtained from the prepreg of the invention isexcellent in heat resistance, interlayer shear strength, and the like,and thus, can be preferably used in automotive members, railroad carmembers, airspace craft members, ship members, house facility members,sports members, light-weight vehicle members, construction and civilengineering members, case bodies for OA instrument, and the like.

EXAMPLES

Hereinafter, the invention will be described in more detail by specificexamples.

(Synthesis Example 1: Manufacturing of Thermoplastic Resin (C-1))

71 parts of PTMG1000 (manufactured by Mitsubishi Chemical Corporation:Polytetramethylene Ether Glycol), 3 parts of 1,4-butanediol, and 26parts of 4,4′-diphenylmethane diisocyanate were mixed, were cast to avat, and were reacted in a condition of 90° C. for 24 hours, and thus, athermoplastic resin (C-1) was prepared. The weight average molecularweight of the thermoplastic resin (C-1) was 50000.

(Synthesis Example 2: Manufacturing of Thermoplastic Resin (C-2))

73 parts of PTMG1000 (manufactured by Mitsubishi Chemical Corporation:Polytetramethylene Ether Glycol), 3 parts of 1,4-butanediol, and 24parts of 4,4′-diphenylmethane diisocyanate were mixed, were cast to avat, and were reacted in a condition of 90° C. for 24 hours, and thus, athermoplastic resin (C-2) was manufactured. The weight average molecularweight of the thermoplastic resin (C-2) was 10000.

(Synthesis Example 3: Manufacturing of Thermoplastic Resin (C-3))

74 parts of PTMG1000 (manufactured by Mitsubishi Chemical Corporation:Polytetramethylene Ether Glycol), 2 parts of 1,4-butanediol, and 24parts of 4,4′-diphenylmethane diisocyanate were mixed, were cast to avat, and were reacted in a condition of 90° C. for 24 hours, and thus, athermoplastic resin (C-3) was manufactured. The weight average molecularweight of the thermoplastic resin (C-3) was 150000.

(Example 1: Manufacturing and Evaluation of Prepreg Resin Composition(1))

19 parts of NEWPOL BPE-20 (manufactured by Sanyo Chemical Industries,Ltd.: EO Adduct of Bisphenol A, Hydroxyl Equivalent of 164 g/eq), 24parts of NEWPOL BPE-40 (manufactured by Sanyo Chemical Industries, Ltd.:EO Adduct of Bisphenol A, Hydroxyl Equivalent of 204 g/eq), and 44 partsof the thermoplastic resin (C-1) were mixed at 150° C. and were cooled,and then, 79 parts of hydroxy ethyl methacrylate, 3 parts of apolymerization initiator (“Trigonox 122-C80”, manufactured by KayakuAkzo Corporation: organic peroxide), 20 parts of a mixture ofpolymethylene polyphenyl polyisocyanate and diphenylmethane diisocyanate(“MILLIONATE MR-200”, manufactured by Tosoh Corporation), and 80 partsof 4,4′-diphenyl methane diisocyanate were mixed, flowed into moldshaving thicknesses of 2 mm and 6 mm, and were aged in a condition of 45°C. for 24 hours, and thus, a prepreg resin composition (1) was obtained.

In addition, 19 parts of NEWPOL BPE-20 (manufactured by Sanyo ChemicalIndustries, Ltd.: EO Adduct of Bisphenol A, Hydroxyl Equivalent of 164g/eq), 24 parts of NEWPOL BPE-40 (manufactured by Sanyo ChemicalIndustries, Ltd.: EO Adduct of Bisphenol A, Hydroxyl Equivalent of 204g/eq), and 44 parts of the thermoplastic resin (C-1) were mixed at 150°C. and were cooled, and then, 79 parts of hydroxy ethyl methacrylate, 3parts of a polymerization initiator (“Trigonox 122-C80”, manufactured byKayaku Akzo Corporation: organic peroxide), 20 parts of a mixture ofpolymethylene polyphenyl polyisocyanate and diphenylmethane diisocyanate(“MILLIONATE MR-200”, manufactured by Tosoh Corporation), and 80 partsof 4,4′-diphenylmethane diisocyanate were mixed and were applied ontoone surface of a PET release film, and then, a carbon fiber(“TRK979PQRW”, manufactured by Mitsubishi Rayon Co., Ltd.) wasimpregnated by a hand lay-up method such that a carbon fiber content was55%, was covered with the same PET release film, and then, was aged in acondition of 45° C. for 24 hours, and thus, a prepreg (1) was prepared.A molar ratio (NCO/OH) of the raw materials in the prepreg (1) excludingthe carbon fiber was 0.93. In addition, a thickness was 0.25 mm.

[Evaluation of Flexibility]

The prepreg resin composition (1) having a thickness of 2 mm, obtainedas described above, was cured in a condition of 150° C. for 30 minutes,and thus, a cured product was obtained. An extension rate of theobtained cured product was measured in accordance with JIS K 7161, andwas evaluated in accordance with the following criteria.

◯: 4% or more

X: Less than 4%

[Evaluation of Impact Resistance]

The prepreg resin composition (1) having a thickness of 6 mm, obtainedas described above, was cured in a condition of 150° C. for 30 minutes,and thus, a cured product was obtained. The obtained cured product wascut out to have a width of 12.7 mm and a length of 150 mm by a diamondcutter, and fracture toughness was measured in accordance with ASTMD5045-99, and was evaluated in accordance with the following criteria.

◯: 1.8 MPa·m^(0.5) or more

X: Less than 1.8 MPa·m^(0.5)

[Preparation of Molded Article]

Eight prepregs (1) obtained as described above were laminated and weresubjected to heat pressure molding by using a plate-shaped mold of 300mm×300 mm×3 mm, in a condition of a mold temperature of 140° C. and amold-closed pressure of 0.98 MPa for 5 minutes, and thus, a moldedarticle (1) was obtained.

[Evaluation of Molding Properties]

A difference between a carbon fiber content rate of the prepreg (1) anda carbon fiber content rate of the molded article (1) obtained asdescribed above was measured, and molding properties were evaluated inaccordance with the following criteria.

◯: The difference in the carbon fiber content rates is less than 5%

Δ: The difference in the carbon fiber content rates is 5% or more andless than 10%

X: The difference in the carbon fiber content rates is 10% or more

[Heat Resistance]

A test piece having a width 5 mm and a length 55 mm was cut out from themolded article (1) obtained as described above, and in the test piece,dynamic viscoelasticity according to both end-bending of a cured productwas measured by using “DMS6100”, manufactured by SII NanotechnologyInc., at a measurement frequency of 1 Hz and a temperature increase rateof 3° C./minute. In a chart of a storage elasticity that was obtained,an intersection between an approximate straight line of a glass regionand a tangential line of a transition region was set to a glasstransition temperature, and heat resistance was evaluated in accordancewith the following criteria.

◯: The glass transition temperature is 120° C. or higher

Δ: The glass transition temperature is 100° C. or higher and lower than120° C.

X: The glass transition temperature is lower than 100° C.

[Evaluation of Flexibility of Molded Article]

A test piece having a width of 15 mm and a length of 60 mm was cut outfrom the molded article (1) obtained as described above, and in the testpiece, bending strength of a fiber unidirectional material in anorthogonal direction (90°) was measured in accordance with JIS K7017,and was evaluated in accordance with the following criteria.

◯: The bending strength is 90 MPa or more

Δ: The bending strength is 70 MPa or more and less than 90 MPa

X: The bending strength is less than 70 MPa

(Example 2: Manufacturing and Evaluation of Prepreg Resin Composition(2))

19 parts of NEWPOL BPE-20 (manufactured by Sanyo Chemical Industries,Ltd.: EO Adduct of Bisphenol A, Hydroxyl Equivalent of 164 g/eq), 24parts of NEWPOL BPE-40 (manufactured by Sanyo Chemical Industries, Ltd.:EO Adduct of Bisphenol A, Hydroxyl Equivalent of 204 g/eq), and 22 partsof the thermoplastic resin (C-1) were mixed at 150° C. and were cooled,and then, 79 parts of hydroxy ethyl methacrylate, 3 parts of apolymerization initiator (“Trigonox 122-C80”, manufactured by KayakuAkzo Corporation: organic peroxide), 20 parts of a mixture ofpolymethylene polyphenyl polyisocyanate and diphenylmethane diisocyanate(“MILLIONATE MR-200”, manufactured by Tosoh Corporation), and 80 partsof 4,4′-diphenyl methane diisocyanate were mixed, flowed into moldshaving thicknesses of 2 mm and 6 mm, and were aged in a condition of 45°C. for 24 hours, and then, a prepreg resin composition (2) was obtained.

In addition, 19 parts of NEWPOL BPE-20 (manufactured by Sanyo ChemicalIndustries, Ltd.: EO Adduct of Bisphenol A, Hydroxyl Equivalent of 164g/eq), 24 parts of NEWPOL BPE-40 (manufactured by Sanyo ChemicalIndustries, Ltd.: EO Adduct of Bisphenol A, Hydroxyl Equivalent of 204g/eq), and 22 parts of the thermoplastic resin (C-1) were mixed at 150°C. and were cooled, and then, 79 parts of hydroxy ethyl methacrylate, 3parts of a polymerization initiator (“Trigonox 122-C80”, manufactured byKayaku Akzo Corporation: organic peroxide), 20 parts of a mixture ofpolymethylene polyphenyl polyisocyanate and diphenylmethane diisocyanate(“MILLIONATE MR-200”, manufactured by Tosoh Corporation), and 80 partsof 4,4′-diphenylmethane diisocyanate were mixed and were applied ontoone surface of a PET release film, and then, a carbon fiber(“TRK979PQRW”, manufactured by Mitsubishi Rayon Co., Ltd.) wasimpregnated by a hand lay-up method such that a carbon fiber content was55%, was covered with the same PET release film, and then, was aged in acondition of 45° C. for 24 hours, and thus, a prepreg (2) was prepared.A molar ratio (NCO/OH) of the raw materials in the prepreg (2) excludingthe carbon fiber was 0.93. In addition, a thickness was 0.25 mm.

(Example 3: Manufacturing and Evaluation of Prepreg Resin Composition(3))

19 parts of NEWPOL BPE-20 (manufactured by Sanyo Chemical Industries,Ltd.: EO Adduct of Bisphenol A, Hydroxyl Equivalent of 164 g/eq), 24parts of NEWPOL BPE-40 (manufactured by Sanyo Chemical Industries, Ltd.:EO Adduct of Bisphenol A, Hydroxyl Equivalent of 204 g/eq), and 11 partsof the thermoplastic resin (C-1) were mixed at 150° C. and were cooled,and then, 79 parts of hydroxy ethyl methacrylate, 22 parts of polyamideparticles (“2001UD”, manufactured by Arkema S.A.), 3 parts of apolymerization initiator (“Trigonox 122-C80”, manufactured by KayakuAkzo Corporation: organic peroxide), 20 parts of a mixture ofpolymethylene polyphenyl polyisocyanate and diphenylmethane diisocyanate(“MILLIONATE MR-200”, manufactured by Tosoh Corporation), and 80 partsof 4,4′-diphenyl methane diisocyanate were mixed, flowed into moldshaving thicknesses of 2 mm and 6 mm, and were aged in a condition of 45°C. for 24 hours, and thus, a prepreg resin composition (3) was obtained.

In addition, 19 parts of NEWPOL BPE-20 (manufactured by Sanyo ChemicalIndustries, Ltd.: EO Adduct of Bisphenol A, Hydroxyl Equivalent of 164g/eq), 24 parts of NEWPOL BPE-40 (manufactured by Sanyo ChemicalIndustries, Ltd.: EO Adduct of Bisphenol A, Hydroxyl Equivalent of 204g/eq), and 11 parts of the thermoplastic resin (C-1) were mixed at 150°C. and were cooled, and then, 79 parts of hydroxy ethyl methacrylate, 22parts of polyamide particles (“2001UD”, manufactured by Arkema S.A.), 3parts of a polymerization initiator (“Trigonox 122-C80”, manufactured byKayaku Akzo Corporation: organic peroxide), 20 parts of a mixture ofpolymethylene polyphenyl polyisocyanate and diphenylmethane diisocyanate(“MILLIONATE MR-200”, manufactured by Tosoh Corporation), and 80 partsof 4,4′-diphenylmethane diisocyanate were mixed and were applied ontoone surface of a PET release film, and then, a carbon fiber(“TRK979PQRW”, manufactured by Mitsubishi Rayon Co., Ltd.) wasimpregnated by a hand lay-up method such that a carbon fiber content was55%, was covered with the same PET release film, and then, was aged in acondition of 45° C. for 24 hours, and thus, a prepreg (3) was prepared.A molar ratio (NCO/OH) of the raw materials in the prepreg (3) excludingthe carbon fiber was 0.93. In addition, a thickness was 0.25 mm.

(Example 4: Manufacturing and Evaluation of Prepreg Resin Composition(4))

19 parts of NEWPOL BPE-20 (manufactured by Sanyo Chemical Industries,Ltd.: EO Adduct of Bisphenol A, Hydroxyl Equivalent of 164 g/eq), 24parts of NEWPOL BPE-40 (manufactured by Sanyo Chemical Industries, Ltd.:EO Adduct of Bisphenol A, Hydroxyl Equivalent of 204 g/eq), and 22 partsof the thermoplastic resin (C-2) were mixed at 150° C. and were cooled,and then, 79 parts of hydroxy ethyl methacrylate, 3 parts of apolymerization initiator (“Trigonox 122-C80”, manufactured by KayakuAkzo Corporation: organic peroxide), 20 parts of a mixture ofpolymethylene polyphenyl polyisocyanate and diphenylmethane diisocyanate(“MILLIONATE MR-200”, manufactured by Tosoh Corporation), and 80 partsof 4,4′-diphenyl methane diisocyanate were mixed, flowed into moldshaving thicknesses of 2 mm and 6 mm, and were aged in a condition of 45°C. for 24 hours, and thus, a prepreg resin composition (4) was obtained.

In addition, 19 parts of NEWPOL BPE-20 (manufactured by Sanyo ChemicalIndustries, Ltd.: EO Adduct of Bisphenol A, Hydroxyl Equivalent of 164g/eq), 24 parts of NEWPOL BPE-40 (manufactured by Sanyo ChemicalIndustries, Ltd.: EO Adduct of Bisphenol A, Hydroxyl Equivalent of 204g/eq), and 22 parts of the thermoplastic resin (C-2) were mixed at 150°C. and were cooled, and then, 79 parts of hydroxy ethyl methacrylate, 3parts of a polymerization initiator (“Trigonox 122-C80”, manufactured byKayaku Akzo Corporation: organic peroxide), 20 parts of a mixture ofpolymethylene polyphenyl polyisocyanate and diphenylmethane diisocyanate(“MILLIONATE MR-200”, manufactured by Tosoh Corporation), and 80 partsof 4,4′-diphenylmethane diisocyanate were mixed and were applied ontoone surface of a PET release film, and then, a carbon fiber(“TRK979PQRW”, manufactured by Mitsubishi Rayon Co., Ltd.) wasimpregnated by a hand lay-up method such that a carbon fiber content was55%, was covered with the same PET release film, and then, was aged in acondition of 45° C. for 24 hours, and thus, a prepreg (4) was prepared.A molar ratio (NCO/OH) of the raw materials in the prepreg (4) excludingthe carbon fiber was 0.93. In addition, a thickness was 0.25 mm.

(Example 5: Manufacturing and Evaluation of Prepreg Resin Composition(5))

19 parts of NEWPOL BPE-20 (manufactured by Sanyo Chemical Industries,Ltd.: EO Adduct of Bisphenol A, Hydroxyl Equivalent of 164 g/eq), 24parts of NEWPOL BPE-40 (manufactured by Sanyo Chemical Industries, Ltd.:EO Adduct of Bisphenol A, Hydroxyl Equivalent of 204 g/eq), 16 parts ofthe thermoplastic resin (C-3) were mixed at 150° C. and were cooled, andthen, 79 parts of hydroxy ethyl methacrylate, 3 parts of apolymerization initiator (“Trigonox 122-C80”, manufactured by KayakuAkzo Corporation: organic peroxide), 20 parts of a mixture ofpolymethylene polyphenyl polyisocyanate and diphenylmethane diisocyanate(“MILLIONATE MR-200”, manufactured by Tosoh Corporation), and 80 partsof 4,4′-diphenyl methane diisocyanate were mixed, flowed into moldshaving thicknesses of 2 mm and 6 mm, and were aged in a condition of 45°C. for 24 hours, and thus, a prepreg resin composition (5) was obtained.

In addition, 19 parts of NEWPOL BPE-20 (manufactured by Sanyo ChemicalIndustries, Ltd.: EO Adduct of Bisphenol A, Hydroxyl Equivalent of 164g/eq), 24 parts of NEWPOL BPE-40 (manufactured by Sanyo ChemicalIndustries, Ltd.: EO Adduct of Bisphenol A, Hydroxyl Equivalent of 204g/eq), and 16 parts of the thermoplastic resin (C-3) were mixed at 150°C. and were cooled, and then, 79 parts of hydroxy ethyl methacrylate, 3parts of a polymerization initiator (“Trigonox 122-C80”, manufactured byKayaku Akzo Corporation: organic peroxide), 20 parts of a mixture ofpolymethylene polyphenyl polyisocyanate and diphenylmethane diisocyanate(“MILLIONATE MR-200”, manufactured by Tosoh Corporation), and 80 partsof 4,4′-diphenylmethane diisocyanate were mixed and were applied ontoone surface of a PET release film, and then, a carbon fiber(“TRK979PQRW”, manufactured by Mitsubishi Rayon Co., Ltd.) wasimpregnated by a hand lay-up method such that a carbon fiber content was55%, was covered with the same PET release film, and then, was aged in acondition of 45° C. for 24 hours, and thus, a prepreg (5) was prepared.A molar ratio (NCO/OH) of the raw materials in the prepreg (5) excludingthe carbon fiber was 0.93. In addition, a thickness was 0.25 mm.

(Comparative Example 1: Preparation and Evaluation of Prepreg ResinComposition (R1))

19 parts of NEWPOL BPE-20 (manufactured by Sanyo Chemical Industries,Ltd.: EO Adduct of Bisphenol A, Hydroxyl Equivalent of 164 g/eq), 24parts of NEWPOL BPE-40 (manufactured by Sanyo Chemical Industries, Ltd.:EO Adduct of Bisphenol A, Hydroxyl Equivalent of 204 g/eq), 79 parts ofhydroxy ethyl methacrylate, 3 parts of a polymerization initiator(“Trigonox 122-C80”, manufactured by Kayaku Akzo Corporation: organicperoxide), 20 parts of a mixture of polymethylene polyphenylpolyisocyanate and diphenyl methane diisocyanate (“MILLIONATE MR-200”,manufactured by Tosoh Corporation), and 80 parts of 4,4′-diphenylmethane diisocyanate were mixed, flowed into molds having thicknesses of2 mm and 6 mm, and were aged in a condition of 45° C. for 24 hours, andthus, a prepreg resin composition (R1) was obtained.

In addition, 19 parts of NEWPOL BPE-20 (manufactured by Sanyo ChemicalIndustries, Ltd.: EO Adduct of Bisphenol A, Hydroxyl Equivalent of 164g/eq), 24 parts of NEWPOL BPE-40 (manufactured by Sanyo ChemicalIndustries, Ltd.: EO Adduct of Bisphenol A, Hydroxyl Equivalent of 204g/eq), 79 parts of hydroxy ethyl methacrylate, 3 parts of apolymerization initiator (“Trigonox 122-C80”, manufactured by KayakuAkzo Corporation: organic peroxide), 20 parts of a mixture ofpolymethylene polyphenyl polyisocyanate and diphenyl methanediisocyanate (“MILLIONATE MR-200”, manufactured by Tosoh Corporation),and 80 parts of 4,4′-diphenyl methane diisocyanate were mixed and wereapplied onto one surface of a PET release film, and then, a carbon fiber(“TRK979PQRW”, manufactured by Mitsubishi Rayon Co., Ltd.) wasimpregnated by a hand lay-up method such that a carbon fiber content was55%, was covered with the same PET release film, and then, was aged in acondition of 45° C. for 24 hours, and thus, a prepreg (R1) was prepared.A molar ratio (NCO/OH) of the raw materials in the prepreg (R1)excluding the carbon fiber was 0.93. In addition, a thickness was 0.25mm.

Flexibility and impact resistance were evaluated as with Example 1,except that the prepreg resin composition (1) used in Example 1 waschanged to the prepreg resin compositions (2) to (5) and (R1).

Further, molded articles (2) to (5) and (R1) were prepared, and moldingproperties and heat resistance were evaluated, as with Example 1, exceptthat the prepreg (1) used in Example 1 was changed to the prepregs (2)to (5) and (R1).

Evaluation results of the prepreg resin compositions (1) to (5) and (R1)obtained as described above are shown in Table 1.

TABLE 1 Example Example Example Example Example Comparative 1 2 3 4 5Example 1 Prepreg resin composition (1) (2) (3) (4) (5) (R1) UrethanePolyisocyanate MR-200 20 20 20 20 20 20 (meth)acrylate (a1) MDI 80 80 8080 80 80 (parts by mass) Polyol (a2) BPE-2C 19 19 19 19 19 19 BPE-4C 2424 24 24 24 24 Hydroxy alkyl HEMA 79 79 79 79 79 79 (meth)acrylate (a3)Thermoplastic (C-1) 44 22 11 resin (C-2) 22 (parts by mass) (C-3) 16Evaluation Flexibility ∘ ∘ ∘ ∘ ∘ x result (extension rate) Impactresistance ∘ ∘ ∘ ∘ ∘ x (fracture toughness) Molding properties ∘ ∘ ∘ ∘ ∘∘ Heat resistance of ∘ ∘ ∘ ∘ ∘ ∘ molded article Flexibility (bending ∘ ∘Δ ∘ ∘ x strength) of molded article

It was checked that the prepreg resin compositions of the invention inExamples 1 to 6 were capable of forming a cured product excellent inflexibility and impact resistance, a prepreg excellent in moldingproperties, and a molded article excellent in heat resistance andflexibility.

On the other hand, Comparative Example 1 is an example in which thethermoplastic resin that is an essential component of the invention isnot contained, and it was checked that the flexibility and the impactresistance of the cured product, and the flexibility of the moldedarticle were insufficient.

1. A prepreg resin composition, comprising: a urethane (meth)acrylate(A) that is a reaction product of polyisocyanate (a1), polyol (a2), andhydroxy alkyl (meth)acrylate (a3); a polymerization initiator (B); and athermoplastic resin (C), as an essential component, wherein thepolyisocyanate (a1) is at least one polyisocyanate selected from2,4′-diphenyl methane diisocyanate, 4,4′-diphenyl methane diisocyanate,a carbodiimide modified product of 4,4′-diphenyl methane diisocyanate,and polymethylene polyphenyl polyisocyanate.
 2. The prepreg resincomposition according to claim 1, wherein the thermoplastic resin (C) isa thermoplastic polyurethane resin containing polyalkylene ether polyolas an essential raw material.
 3. The prepreg resin composition accordingto claim 1, wherein the thermoplastic resin (C) has a weight averagemolecular weight of 5,000 to 1,000,000.
 4. The prepreg resin compositionaccording to claim 1, wherein the thermoplastic resin (C) is in a rangeof 1% by mass to 25% by mass.
 5. A prepreg comprising: the prepreg resincomposition according to claim 1; and a reinforcing fiber (D).
 6. Amolded article, comprising: a product obtained by curing the prepregaccording to claim
 5. 7. The prepreg resin composition according toclaim 2, wherein the thermoplastic resin (C) has a weight averagemolecular weight of 5,000 to 1,000,000.
 8. The prepreg resin compositionaccording to claim 2, wherein the thermoplastic resin (C) is in a rangeof 1% by mass to 25% by mass.
 9. The prepreg resin composition accordingto claim 3, wherein the thermoplastic resin (C) is in a range of 1% bymass to 25% by mass.
 10. The prepreg resin composition according toclaim 7, wherein the thermoplastic resin (C) is in a range of 1% by massto 25% by mass.
 11. A prepreg comprising: the prepreg resin compositionaccording to claim 2; and a reinforcing fiber (D).
 12. A prepregcomprising: the prepreg resin composition according to claim 3; and areinforcing fiber (D).
 13. A prepreg comprising: the prepreg resincomposition according to claim 4; and a reinforcing fiber (D).
 14. Aprepreg comprising: the prepreg resin composition according to claim 7;and a reinforcing fiber (D).
 15. A prepreg comprising: the prepreg resincomposition according to claim 8; and a reinforcing fiber (D).
 16. Aprepreg comprising: the prepreg resin composition according to claim 9;and a reinforcing fiber (D).
 17. A prepreg comprising: the prepreg resincomposition according to claim 10; and a reinforcing fiber (D).
 18. Amolded article, comprising: a product obtained by curing the prepregaccording to claim
 11. 19. A molded article, comprising: a productobtained by curing the prepreg according to claim
 12. 20. A moldedarticle, comprising: a product obtained by curing the prepreg accordingto claim 13.